The present invention relates to bone-fixing screws comprising a thread adapted to be screwed into a bone, and a fixing means located at the end thereof which is designed for installing rods into the screw.
In order to maintain bones in a specified orientation relationship, there are various known techniques for screwing a bone-fixing screw (as an implant) into bones in various parts of the body, such as the spine, and combining rods with said implanted screw so that the rods will be positioned alongside the bones. The screws of prior art are provided with a rod-fixing means. The rod-fixing means have an opening that is located either parallel to the axial direction of thread or on the side thereof, but both solutions have their own problems; inserted rods slipped out of place easily with the former parallel arrangement, while with the latter, operators had to insert a rod at right angles to the axis of the thread, which proved to be a difficult procedure.